4.19 System Administration

If you have a system available with the root password do the following:

1. Back up the system (dump, rdump, or tar).
2. Add a new user.
3. Create a list of all executable set user id and set group id files owned by root with file lengths and modification times.
4. Restore a file from your backup.

• Backup and Restore
  1. Look in your area with the du command to find a subdirectory with less than 1 Mbyte of data.
  2. Use tar to create a file that contains all of the files in your <1Mbyte area. The command should look something like this:

      
     cd /var/tmp/ 
     tar -cvf your-user-name.tar ~/  
     

     This will create a tar file in /var/tmp/ with your user-name as the file name. tar will try to tar its own output if given the chance.
  3. Do a

     ls -l
     

     to find out the size of the archive file prior to the compression. Write down the size of the file; it will be deleted by the compress command. Compress the files using the compress command:

      
     compress your-user-name.tar 
     

     Compare the size of

     your-user-name.tar
     

     and

     your-user-nametar.Z.
     

     Write this on your final printout. Write down the compression percentage.
  4. Uncompress the file.

      
     uncompress your-user-name.tar.Z
     

  5. Some systems might not have the gzip and gunzip commands. Skip this section if you must. Re-compress the files using the gnu gzip command:

      
     gzip your-user-name.tar
     

     Compare the size of

     your-user-name.tar 
     

     and

     your-user-name.tar.gz
     

     Write the result of your comparison on your final output.
  6. (Optional) Copy this to a floppy disk using Kermit or ftp. There are PC systems in the computer lab (in room BUS R6E)that can be used to do this, or you can do it over the Internet. Make sure that the file is transferred as a binary file.
  7. Create a new subdirectory in your area (called "backup-dir"). Uncompress your file into this area, then expand the tar file to restore your files. The first cd will take you back to your home directory.

      
     cd
     mkdir backup-dir 
     cd backup-dir 
     tar -xvzf /var/tmp/your-user-name.tar.gz
     

     The -x option is for "eXtract". The -v option is for verbose. It will list the file names. The -z option will decompress the tar file on the fly. The -f option is for a following file name. tar defaults to a tape drive.
  8. Save a copy of a recursive directory to be turned in. For this lab turn in all of the requested commands together as a single printout.

     cd
     ls -lR 
     

     This should include your backup-dir and the original subdirectory. Remember to print all of your results together as a single printout for this lab.
• Monitoring the System
  1. Use the df command to look at the file systems on gort. Save a copy of the results.
  2. Use the mount command to look at the file systems mounted on the system. Append this to your output.
  3. Use finger, ps -ae, and ps -al to see what else is on the system. ps is a process status program. It shows what you and other people have running. Append the results of these commands to the file from the previous step.
  4. Run the top command. This shows the top processes on the system. End the command with a q.
  5. Look for suid programs owned by root.

     find /usr/bin -user root -perm -4000 -print
     

     Append this file to your printout.
• System maintenance
  1. Use the following command to copy a set of files keeping the existing permission bits.

     cd
     mkdir from-dir
     mkdir to-dir
     cd from-dir
     ** Put some files in the from-dir directory **
     tar -cf - . | ( cd to-dir; tar xvf - )
     

     Make sure that the to-dir is not in the from-dir. You may want to remove both from-dir and to-dir.
  2. Use the dmesg command to see the "power-up" messages for the system. Include this information in your "turn-in" file.
  3. Clean up your section of the file system by removing unwanted files and directories. You can use rm -r backup-dir to remove all of the files and the new backup-dir sub-directory. Keep your floppy as long as you want it. Also delete /var/tmp/your-user-name.

your-name
TABER CSC137
Lab 4.19: System Administration